Many or most current seat recliners "work" on the principle of mesh gear teeth mounted on a rotating shaft. Partial (sector) gear and planetary gear systems are commonly utilized. Another common current seat recliner mechanism is a sliding cylinder mechanism within a locking spring "Porter" device. Both provide a mechanism to recline a seat back relative to the lower seat frame.
An object of the present invention is to provide an improved recliner mechanism for a vehicle seat that is strong, compact, and relatively inexpensive. Another object of the present invention is to provide a recliner that is continually adjustable and has improved safety characteristics under crash conditions, especially when the invention is used for "restraint seating", which is seating wherein the upper end of a shoulder safety belt is mounted to the seat back itself, such that the seat back restrains crash stresses.